JP2021007275A - Spork-type motor, motor for vehicle, unmanned flying body and electric assist device - Google Patents

Abstract

To achieve low vibration while holding a dispersion intensity of a permanent magnet.SOLUTION: A spork-type motor comprises a stator, and a rotor 30 which can relatively rotate around a central axis extending in the vertical direction to the stator. The rotor comprises: a rotor core which has a shaft arranged along the central axis and plural core piece parts 34 arranged to be separated from each other along the circumferential direction on an outer side in a radial direction of the shaft; and plural permanent magnets 33 which are alternately arranged with the core piece parts in the circumferential direction on the outer side in the radial direction of the shaft, and magnetize the core piece parts. The core piece parts comprises: splash prevention parts 1N, 1S which cover a part of the outer side in the radial direction of the permanent magnet; and notch parts 2N, 2S which are arranged on the outer side in the radial direction than the splash prevention part, toward a center line from a position in which a distance in the circumferential direction from the center line in the circumferential direction of the permanent magnet covered by the splash prevention part is longer than that of an end of the splash prevention part.SELECTED DRAWING: Figure 2

Description

The present invention relates to spoke type motors, vehicle motors, unmanned aerial vehicles and electric assist devices.

In the spoke type motor, it is necessary to adopt a structure that prevents the permanent magnets from scattering due to the centrifugal force when the rotor rotates. As a structure for preventing the scattering of the permanent magnet, a structure for preventing the scattering of the permanent magnet by resin-molding the permanent magnet and the rotor core is also known.

A structure that prevents the scattering of permanent magnets by devising the shape of the rotor core is known. For example, Patent Document 1 discloses a structure in which a protrusion provided on a rotor core prevents the permanent magnet from scattering. For example, Patent Document 2 discloses a structure in which a permanent magnet is inserted into a rotor core to prevent the permanent magnet from scattering.

Japanese Unexamined Patent Publication No. 8-909599 Japanese Unexamined Patent Publication No. 2000-152534

However, in the structure that prevents the permanent magnets from scattering by the resin mold, the strength may be insufficient depending on the rotation speed of the rotor. As described in Patent Document 1 and Patent Document 2, in the structure in which a part of the rotor core covers the radial outside of the permanent magnet, the magnetic flux distribution is disturbed by the part of the rotor core covering the radial outside of the permanent magnet. It will be caused. When the magnetic flux distribution is disturbed, the vibration may increase due to the pulsation of the cogging torque or the like. When the magnetic flux distribution is disturbed, the vibration having a high electric angle order may increase.

One aspect of the present invention has been made in consideration of the above points, and is a spoke type motor capable of achieving low vibration while maintaining the scattering prevention strength of the permanent magnet, and a vehicle provided with the spoke type motor. It is an object of the present invention to provide a motor, an unmanned vehicle, and an electric assist device.

According to the first aspect of the present invention, the stator includes a stator and a rotor that is relatively rotatable about a central axis extending in the vertical direction with respect to the stator, and the rotor is provided along the central axis. A shaft to be arranged, a rotor core having a plurality of core pieces arranged separately from each other along the circumferential direction on the radial outer side of the shaft, and the core piece alternately arranged on the radial outer side of the shaft in the circumferential direction. The core piece includes a plurality of permanent magnets that excite the core piece, and the core piece has a shatterproof portion that covers a part of the permanent magnet on the radial outer side, and a shatterproof portion that is radially outer than the shatterproof portion. A spoke type having a notch arranged from a position where the circumferential distance of the permanent magnet covered by the shatterproof portion from the circumferential center line is longer than the end portion of the shatterproof portion toward the center line. Motors are provided.

According to the second aspect of the present invention, as the motor for driving the dual clutch transmission, a vehicle motor including the spoke type motor of the first aspect is provided.

According to a third aspect of the present invention, there is provided an unmanned aerial vehicle comprising the spoke type motor of the first aspect.

According to a fourth aspect of the present invention, there is provided an electrically assisted device including the spoke type motor of the first aspect.

According to one aspect of the present invention, it is possible to realize low vibration while maintaining the scattering prevention strength of the permanent magnet.

FIG. 1 is a cross-sectional view showing a motor of the first embodiment. FIG. 2 is a view showing a rotor of the first embodiment, and is a sectional view taken along line IV-IV shown in FIG. FIG. 3 is a diagram showing the relationship between the electric angle and the radial magnetic flux density of the tooth portion in the stator. FIG. 4 is a diagram showing the relationship between the electric angle order and the radial magnetic flux density of the tooth portion. FIG. 5 is a diagram showing the relationship between the electric angular order (fourth order) and the radial electromagnetic force. FIG. 6 is a diagram showing the relationship between the electric angular order (10th order) and the radial electromagnetic force. FIG. 7 is a partial cross-sectional view showing the rotor of the second embodiment. FIG. 8 is a view of the rotor of the second embodiment as viewed from the outside in the radial direction. FIG. 9 is a perspective view showing an example of the unmanned aerial vehicle 2000. FIG. 10 is a front view of the electrically power assisted bicycle 3000.

Hereinafter, the spoke type motor according to the embodiment of the present invention will be described with reference to the drawings. The scope of the present invention is not limited to the following embodiments, and can be arbitrarily changed within the scope of the technical idea of the present invention. Further, in the following drawings, in order to make each configuration easy to understand, the scale and number of each structure may be different from the actual structure.

Further, in the drawings, the XYZ coordinate system is shown as a three-dimensional Cartesian coordinate system as appropriate. In the XYZ coordinate system, the Z-axis direction is a direction parallel to the axial direction of the central axis J shown in FIG. The X-axis direction is a direction orthogonal to the Z-axis direction and is the left-right direction in FIG. The Y-axis direction is a direction orthogonal to both the X-axis direction and the Z-axis direction. Further, the circumferential direction centered on the central axis J is the θZ direction. In the θZ direction, the clockwise direction is positive when viewed from the −Z side toward the + Z side, and the counterclockwise direction is negative when viewed from the −Z side toward the + Z side.

Further, in the following description, the extending direction of the central axis J (Z-axis direction) is defined as the vertical direction.
The positive side (+ Z side) in the Z-axis direction is called "upper side (upper side in the axial direction)", and the negative side (-Z side) in the Z-axis direction is called "lower side". The vertical direction, the upper side, and the lower side are names used only for explanation, and do not limit the actual positional relationship or direction. Unless otherwise specified, the direction parallel to the central axis J (Z-axis direction) is simply referred to as the "axial direction", and the radial direction centered on the central axis J is simply referred to as the "radial direction". The circumferential direction (θZ direction) centered on, that is, the circumference of the central axis J is simply referred to as the “circumferential direction”.

Further, the side that advances in the positive direction in the θZ direction (+ θZ side, one side in the circumferential direction) is called the “drive side”, and the side that advances in the negative direction in the θZ direction (−θZ side, the other side in the circumferential direction) is called the “drive side”. Called the "reverse drive side". It should be noted that the driving side and the counter-driving side are names used only for explanation and do not limit the actual driving direction.

In the present specification, "extending in the axial direction" means not only extending in the strict axial direction (Z-axis direction) but also extending in a direction inclined within a range of less than 45 ° with respect to the axial direction. Including. Further, in the present specification, "extending in the radial direction" means that the term extends in the radial direction, that is, in the direction perpendicular to the axial direction (Z-axis direction), and 45 ° with respect to the radial direction. Including the case where it extends in a tilted direction within a range of less than.

[Spoke type motor]
<First Embodiment>
FIG. 1 is a cross-sectional view showing a spoke type motor 10 of the first embodiment (in the following description, simply referred to as a motor 10). As shown in FIG. 1, the motor 10 of the present embodiment includes a housing 20, a rotor 30 having a shaft 31, a stator 40, a lower bearing (bearing) 51, an upper bearing (bearing) 52, and a bus bar unit. 60 and.

The housing 20 houses the rotor 30, the stator 40, the lower bearing 51, the upper bearing 52, and the bus bar unit 60. The housing 20 has a lower housing 21 and an upper housing 22. The lower housing 21 has a tubular shape that opens on both sides (± Z side) in the axial direction. The upper housing 22 is fixed to the upper (+ Z side) end of the lower housing 21. The upper housing 22 covers the upper side of the rotor 30 and the stator 40.

The stator 40 is held inside the lower housing 21. The stator 40 is located radially outside the rotor 30. The stator 40 has a core back portion 41, a teeth portion 42, a coil 43, and a bobbin 44. The shape of the core back portion 41 is, for example, a cylindrical shape concentric with the central axis J. The outer surface of the core back portion 41 is fixed to the inner surface of the lower housing 21.

The teeth portion 42 extends from the inner surface of the core back portion 41 toward the shaft 31. Although not shown in FIG. 1, a plurality of tooth portions 42 are provided and are arranged at equal intervals in the circumferential direction. The bobbin 44 is attached to each tooth portion 42. The coil 43 is wound around each tooth portion 42 via a bobbin 44.

The bus bar unit 60 is located on the upper side (+ Z side) of the stator 40. The bus bar unit 60 has a connector portion 62. An external power supply (not shown) is connected to the connector portion 62. The bus bar unit 60 has a wiring member that is electrically connected to the coil 43 of the stator 40. One end of the wiring member is exposed to the outside of the motor 10 via the connector portion 62. As a result, power is supplied to the coil 43 from the external power supply via the wiring member. The bus bar unit 60 has a bearing holding portion 61.

The lower bearing 51 and the upper bearing 52 support the shaft 31. The lower bearing 51 is located on the lower side (−Z side) of the stator 40. The lower bearing 51 is held in the lower housing 21. The upper bearing 52 is located on the upper side (+ Z side) of the stator 40. The upper bearing 52 is held by the bearing holding portion 61 of the bus bar unit 60.

The rotor 30 has a shaft 31 and a rotor core 32. The shaft 31 is centered on a central axis J extending in the vertical direction (Z-axis direction). The rotor core 32 is located radially outside the shaft 31. In the present embodiment, the rotor core 32 is fixed to the outer peripheral surface of the shaft 31. In the present embodiment, for example, the rotor 30 rotates counterclockwise about the central axis J, that is, from the counterclockwise drive side (−θZ side) to the drive side (+ θZ side) when viewed from the upper side (+ Z side).

FIG. 2 is a partially enlarged view of the IV-IV cross section in FIG.

As shown in FIG. 2, the rotor core 32 has a plurality of permanent magnets 33 and a plurality of core piece portions 34. That is, the rotor 30 has a plurality of permanent magnets 33 and a plurality of core piece portions 34. The permanent magnet 33 excites the core piece portion 34. The permanent magnets 33 are arranged alternately with the core piece portions 34 in the circumferential direction.

The permanent magnet 33 is inserted into a magnet insertion hole 38, which will be described later. The permanent magnet 33 has permanent magnets 33A and 33B. The permanent magnets 33A and the permanent magnets 33B are alternately arranged along the circumferential direction. In the following description, the permanent magnet 33A and the permanent magnet 33B may be described as the permanent magnet 33 as a representative.

The permanent magnets 33A and 33B have two magnetic poles arranged along the circumferential direction. The permanent magnet 33A has, for example, an N pole on the driving side (+ θZ side) and an S pole on the opposite driving side (−θZ side). The permanent magnet 33B has, for example, an S pole on the driving side (+ θZ side) and an N pole on the opposite driving side (−θZ side). As a result, the magnetic poles of the permanent magnets 33A and 33B adjacent to each other in the circumferential direction have the same poles facing each other in the circumferential direction.

The permanent magnet 33A and the permanent magnet 33B have the same configuration except that the arrangement of the magnetic poles in the circumferential direction is different. Therefore, in the following description, only the permanent magnet 33A may be described as a representative.

The permanent magnet 33A extends in the radial direction. The shape of the cross section orthogonal to the axial direction (Z-axis direction) of the permanent magnet 33A is, for example, a rectangular shape. In addition, in this specification, a rectangular shape includes a substantially rectangular shape. The substantially rectangular shape includes, for example, a state in which the corners of the rectangle are chamfered.

In this embodiment, for example, five permanent magnets 33A are provided. For example, five permanent magnets 33B are provided.

The core piece portion 34 has an inner core portion 34I and an outer core portion 34O. The inner core portion 34I is located on the radial outside of the shaft 31 and on the radial inside of the permanent magnets 33A and 33B. The inner core portion 34I has a support portion 35 that supports the radial inside of the permanent magnets 33A and 33B. The core piece portion 34 has a cavity portion 37 around the support portion 35. The cavity 37 is a flux barrier that suppresses magnetic flux leakage in the support 35.

The outer core portion 34O has core piece portions 34N and 34S. The core piece portions 34N and 34S are arranged on the outer side of the shaft 31 in the radial direction so as to be separated from each other along the circumferential direction. The core piece portion 34N and the core piece portion 34S are alternately arranged along the circumferential direction. The core piece portion 34N is located between the north pole of the permanent magnet 33A and the north pole of the permanent magnet 33B. As a result, the core piece portion 34N is excited to the N pole. The core piece portion 34S is located between the S pole of the permanent magnet 33A and the S pole of the permanent magnet 33B. As a result, the core piece portion 34S is excited to the S pole.

A magnet insertion hole 38 is arranged between the adjacent core piece portions 34N and the core piece portion 34S in the circumferential direction. The magnet insertion hole 38 is a hole into which the permanent magnet 33A is inserted. The magnet insertion hole portion 38 is adjacent to the core piece portions 34N and 34S that are adjacent to each other in the circumferential direction. The core piece portion 34N has a facing surface 36N facing the north poles of the permanent magnets 33A and 33B in the circumferential direction. The core piece portion 34S has a facing surface 36S facing the S poles of the permanent magnets 33A and 33B in the circumferential direction. That is, the facing surface 36N and the facing surface 36S are a part of the inner surface of the magnet insertion hole 38.

The core piece portion 34N has a shatterproof portion 1N and a notch portion 2N. The shatterproof portion 1N covers a part of the permanent magnets 33A and 33B on the outer side in the radial direction. The shatterproof portion 1N is provided in the entire axial direction of the rotor core 32. The shatterproof portion 1N is arranged at a position radially outside the permanent magnets 33A and 33B. The shatterproof portion 1N has an end portion 1Na facing the center line C side in the circumferential direction of the permanent magnets 33A and 33B covered by the shatterproof portion 1N. The circumferential distance from the facing surface 36N to the end 1Na is shorter than the circumferential distance from the facing surface 36N to the center line C. The circumferential distance from the center line C to the end portion 1Na is shorter than the circumferential distance from the center line C to the north pole side end faces of the permanent magnets 33A and 33B.

The core piece portion 34S has a shatterproof portion 1S and a notch portion 2S. The shatterproof portion 1S covers a part of the permanent magnets 33A and 33B on the outer side in the radial direction. The shatterproof portion 1S is provided in the entire axial direction of the rotor core 32. The shatterproof portion 1S is arranged at a position radially outside the permanent magnets 33A and 33B. The shatterproof portion 1S has an end portion 1Sa facing the center line C side in the circumferential direction of the permanent magnets 33A and 33B covered by the shatterproof portion 1S. The circumferential distance from the facing surface 36S to the end 1Sa is shorter than the circumferential distance from the facing surface 36N to the center line C. The circumferential distance from the center line C to the end portion 1Sa is shorter than the circumferential distance from the center line C to the S pole side end faces of the permanent magnets 33A and 33B.

When the rotor 30 rotates about the central axis J, the shatterproof portions 1N and 1S support the permanent magnets 33A and 33B on the outer side in the radial direction. By supporting the permanent magnets 33A and 33B on the outer side in the radial direction, the scattering prevention portions 1N and 1S can prevent the permanent magnets 33A and 33B from scattering outward in the radial direction due to the centrifugal force accompanying the rotation of the rotor 30. Since the scattering prevention portions 1N and 1S are provided in the entire axial direction of the rotor core 32, it is possible to more reliably prevent the permanent magnets 33A and 33B from scattering outward in the radial direction due to the centrifugal force.

The notch portion 2N is arranged radially outside the shatterproof portion 1N. The notch 2N is provided in the entire axial direction of the rotor core 32. The notch portion 2N is arranged toward the center line C from a position where the distance from the center line C in the circumferential direction is longer than the end portion 1Na of the scattering prevention portion 1N. The circumferential end 2Nb of the notch 2N near the center line C has the same circumferential distance from the center line C as the distance to the end 1Na of the shatterproof portion 1N. Since the end 2Nb of the notch 2N is a position in space, a virtual position is shown. The end 2Nb of the notch 2N overlaps the permanent magnets 33A and 33B in the radial direction.

The circumferential end 2Na of the notch 2N on the side far from the center line C has a circumferential distance from the center line C longer than the distance to the N pole side end faces of the permanent magnets 33A and 33B. That is, the cutout portion 2N extends from the end portion 2Nb having the same circumferential position as the end portion 1Na of the shatterproof portion 1N to the N pole side end faces of the permanent magnets 33A and 33B having a circumferential distance from the center line C. It is provided between the end 2Na, which is longer than the distance. The end 2Na on the side far from the center line C of the notch 2N does not overlap with the permanent magnets 33A and 33B in the radial direction. The position of the notch 2N inside in the radial direction is preferably close to the central axis J within a range in which the scattering prevention portion 1N can prevent the permanent magnets 33A and 33B from scattering outward in the radial direction.

The notch portion 2S is arranged radially outside the shatterproof portion 1S. The notch 2S is provided in the entire axial direction of the rotor core 32. The cutout portion 2S is arranged toward the center line C from a position where the distance from the center line C in the circumferential direction is longer than the end portion 1Sa of the scattering prevention portion 1S. The circumferential end 2Sb of the notch 2S near the center line C has the same circumferential distance from the center line C as the distance to the end 1Sa of the shatterproof portion 1S. Since the end 2Sb of the notch 2S is a position in space, a virtual position is shown. The end portion 2Sb of the notch portion 2S overlaps the permanent magnets 33A and 33B in the radial direction.

The circumferential end 2Sa of the notch 2S far from the center line C has a circumferential distance from the center line C longer than the distance to the S pole side end faces of the permanent magnets 33A and 33B. That is, the cutout portion 2S extends from the end portion 2Sb having the same circumferential position as the end portion 1Sa of the shatterproof portion 1S to the S pole side end faces of the permanent magnets 33A and 33B having a circumferential distance from the center line C. It is provided between the end 2Sa, which is longer than the distance. The end portion 2Sa on the side far from the center line C of the notch portion 2S does not overlap with the permanent magnets 33A and 33B in the radial direction. The position of the notch 2S inside in the radial direction is close to the central axis J within a range in which the scattering prevention portion 1S can prevent the permanent magnets 33A and 33B from scattering outward in the radial direction in order to reduce the disturbance of the magnetic flux distribution. Is preferable.

The core piece portion 34N and the core piece portion 34S have the same configuration except that the arrangement of the magnetic poles in the circumferential direction excited by the permanent magnets 33A and 33B is different. Therefore, in the following description, only the core piece portion 34N may be described as a representative.

By setting the circumferential position of the end portion 2Na of the notch portion 2N in the core piece portion 34N based on the pole logarithm and the electric angle order of the permanent magnets 33A and 33B, the radial magnetic flux density of the electric angle order is set. , It is possible to cancel by giving the magnetic flux density of the opposite phase.

Assuming that the number of pole pairs of the permanent magnets 33A and 33B is P and the order of the electric angle is N, the angle Δθ between the end 2Na of the notch 2N centered on the central axis J and the center line C is the following equation (1). ).
Δθ = (π / P) × (1 / N)… (1)

The effective range in which the above-mentioned magnetic flux densities of opposite phases can be applied and canceled according to the position of the end 2Na is 0.5 times or more and 1.5 times or less of Δθ obtained by the above equation (1). is there. That is, in order to counteract the magnetic flux density in the opposite phase with respect to the radial magnetic flux density of the electric angle order N, the following equation (2) may be satisfied.
0.5 × (π / P) × (1 / N) ≦ Δθ ≦ 1.5 × (π / P) × (1 / N)… (2)

FIG. 3 is a diagram showing the relationship between the electric angle (deg) and the radial magnetic flux density (T) of the teeth portion 42 in the stator 40. As an example, the electrical angles in FIG. 3 are such that the position of the center line C in the circumferential direction is 150 ° and 330 ° C., and the center position in the circumferential direction of the core piece portion 34N is 60 °. The graph G1 shown by the broken line in FIG. 3 shows the relationship between the electric angle (deg) and the radial magnetic flux density (T) of the teeth portion 42 when the core piece portion 34N is not provided with the notch portion 2N. The graph G2 shown by the solid line in FIG. 3 shows the relationship between the electric angle (deg) and the radial magnetic flux density (T) of the teeth portion 42 when the notch portion 2N is provided in the core piece portion 34N.

When the scattering prevention portion 1N of the core piece portion 34N covers a part of the permanent magnets 33A and 33B in the radial direction and the notch portion 2N is not provided, the magnetic flux distribution is disturbed as shown in FIG. The graph G1 deviates from the generated sine waveform. When the scattering prevention portion 1N of the core piece portion 34N covers a part of the permanent magnets 33A and 33B on the radial side and the notch portion 2N is provided, the graph G2 has a sinusoidal magnetic flux density in the radial direction. The graph G2 has a sinusoidal waveform in which the radial magnetic flux density changes between the maximum value T1 and the minimum value T2, while the graph G1 has the maximum radial magnetic flux density T3 (T3 <T1) and the minimum value T4 ( The waveform deviates from the sinusoidal waveform that changes between T4> T2).

FIG. 4 is a diagram showing the relationship between the electric angular order and the radial magnetic flux density (T) of the teeth portion 42. The graph on the left side showing each order of the electric angle in FIG. 4 without hatching shows the relationship between the electric angle order and the radial magnetic flux density when the core piece portion 34N is not provided with the notch portion 2N. The graph on the right side, which is shown with hatching for each order of the electric angle in FIG. 4, shows the relationship between the electric angle order and the radial magnetic flux density when the notch portion 2N is provided in the core piece portion 34N.

In the motor 10, the spatial harmonic component of the magnetic flux distribution may contribute to the higher-order vibration component. In the spoke type motor 10, as shown in FIG. 4, the tertiary component and the ninth component have a particularly adverse effect on higher-order vibration.

By setting the position of the end portion 2Na in the notch portion 2N based on the equations (1) and (2), the radial electromagnetic force of the electric angle order (N + 1) acting on the teeth portion 42 can be reduced. By reducing the radial electromagnetic force acting on the teeth portion 42, the radial vibration of the motor 10 can be reduced.

For example, the core piece portion 34N in which the position of the end 2Na is set based on the equations (1), (2) and the third-order electric angle, and the end based on the equations (1), (2) and the ninth-order electric angle. The amplitude of the radial magnetic flux density was confirmed for each of the core piece portions 34N in which the positions of the portions 2Na were set. As shown in FIG. 4, the amplitude of the radial magnetic flux density was the same as that without the notch 2N for the 9th-order electric angle, but the notch 2N was not provided for the 3rd-order electric angle. On the other hand, the amplitude of the radial magnetic flux density could be reduced from the maximum value T11 to the maximum value T12 by about 17%.

FIG. 5 is a diagram showing the relationship between the electric angular order (fourth order) and the radial electromagnetic force. In FIG. 5, the graph on the left side shown without hatching shows the relationship between the electric angular order and the radial electromagnetic force when the core piece portion 34N is not provided with the notch portion 2N. In FIG. 5, the graph on the right side shown with hatching shows the relationship between the electrical angular order (fourth order) and the radial electromagnetic force when the core piece portion 34N is provided with the notch portion 2N.

As shown in FIG. 5, the radial electromagnetic force when the position of the end portion 2Na is set to the core piece portion 34N based on the third-order electric angle is the electromagnetic force when the core piece portion 34N is not provided with the notch portion 2N. It was possible to reduce the force to about 12%.

FIG. 6 is a diagram showing the relationship between the electric angular order (10th order) and the radial electromagnetic force. In FIG. 6, the graph on the left side shown without hatching shows the relationship between the electric angular order and the radial electromagnetic force when the core piece portion 34N is not provided with the notch portion 2N. In FIG. 6, the graph on the right side shown with hatching shows the relationship between the electric angular order (10th order) and the radial electromagnetic force when the notch portion 2N is provided in the core piece portion 34N.

As shown in FIG. 6, the radial electromagnetic force when the position of the end portion 2Na is set to the core piece portion 34N based on the ninth-order electric angle is the electromagnetic force when the core piece portion 34N is not provided with the notch portion 2N. It was possible to reduce the force to about 74%.

<Second Embodiment>
In the second embodiment, with respect to the first embodiment, the position in the circumferential direction of the end portion 2Na on the side far from the center position C of the notch portion 2N and the circumference of the end portion 2Sa on the side far from the center position C of the notch portion 2S. Different in directional position. The same configuration as that of the first embodiment may be omitted from the description by appropriately assigning the same reference numerals.

FIG. 7 is a partial cross-sectional view showing the rotor 30 of the present embodiment. As shown in FIG. 7, the end portion 2Na on the side far from the center position C of the notch portion 2N overlaps the permanent magnets 33A and 33B in the radial direction. The end portion 2Sa on the side far from the center position C of the notch portion 2S overlaps the permanent magnets 33A and 33B in the radial direction.

The magnetic flux in the present embodiment is directed toward the teeth portion 42 from the region of the core piece portion 34N that is farther from the center position C than the end portion 2Na and overlaps with the permanent magnets 33A and 33B in the radial direction. The magnetic flux in the present embodiment is directed from the teeth portion 42 to a region of the core piece portion 34S that overlaps the permanent magnets 33A and 33B in the radial direction on the side farther from the center position C than the end portion 2Sa. Therefore, even when the notch portions 2N and 2S are provided in the core piece portions 34N and 34S, it is possible to suppress excessive concentration of the magnetic flux flow by increasing the region in which the magnetic flux flows.

<Third Embodiment>
The third embodiment is different from the first embodiment in that the shatterproof portions 1N and 1S are provided in a part of the rotor core 32 in the axial direction. The same configuration as that of the first embodiment may be omitted from the description by appropriately assigning the same reference numerals.

FIG. 8 is a view of the permanent magnets 33A and 33B and the core piece portions 34N and 34S viewed from the outside in the radial direction. The core piece portion 34N has a plurality of lamination LNs laminated in the axial direction. Of the plurality of lamination LNs, the lamination LNas arranged at both ends in the axial direction have shatterproof portions 1N covering a part of the permanent magnets 33A and 33B on the radial outer side. The cutout portion 2N is provided in both the lamination LNa having the shatterproof portion 1N and the lamination LN not having the shatterproof portion 1N. That is, the notch 2N is provided in all the lamination LNs.

The core piece portion 34S has a plurality of lamination LS laminated in the axial direction. Of the plurality of lamination LSs, the lamination LSs arranged at both ends in the axial direction have shatterproof portions 1S that cover a part of the permanent magnets 33A and 33B on the outer side in the radial direction. The cutout portion 2S is provided in both the lamination LSa having the shatterproof portion 1S and the lamination LS not having the shatterproof portion 1S. That is, the notch 2S is provided in all lamination LS.

In the rotor 30 of the present embodiment, the scattering prevention portions 1N and 1S prevent the permanent magnets 33A and 33B from scattering outward in the radial direction due to centrifugal force, and only the lamination LSa is one of the radial outer sides of the permanent magnets 33A and 33B. Since the portion is covered, the weight of the rotor 30 can be reduced. In the rotor 30 of the present embodiment, since the notch 2N is provided in all the lamination LNs and the notch 2S is provided in all the lamination LSs, the influence of the magnetic flux leakage in the axial direction can be reduced.

In the motor 10 described in the above embodiment, the permanent magnets 33A and 33B and the core piece portions 34N and 34S may be molded with a resin material. When the permanent magnets 33A and 33B and the core piece portions 34N and 34S are molded with a resin material, a part of the permanent magnets 33A and 33B on the radial outer side can be covered with the resin material. The resin material that covers a part of the radial outer side of the permanent magnets 33A and 33B prevents the permanent magnets 33A and 33B from scattering outward in the radial direction due to centrifugal force as a second scattering prevention portion. By using the scattering prevention portions 1N and 1S and the resin material in combination with the scattering prevention of the permanent magnets 33A and 33B, the scattering of the permanent magnets 33A and 33B can be prevented more reliably. By using the scattering prevention of the permanent magnets 33A and 33B together with the scattering prevention portions 1N and 1S and the resin material, the positions of the notches 2N and 2S inside in the radial direction can be made closer to the central axis J. Disturbance of the magnetic flux distribution can be reduced by making the positions of the notches 2N and 2S inside in the radial direction close to the central axis J.

The application of the motor 10 to which the present invention is applied is not particularly limited, and is used, for example, in gear selection of a transmission such as a dual clutch transmission (DCT) mounted on a vehicle, or in driving a clutch. By using the motor 10 to which the present invention is applied, it is possible to reduce the vibration of the vehicle motor.

The motor 10 to which the present invention is applied is used, for example, in an unmanned aerial vehicle. FIG. 9 is a perspective view showing an example of the unmanned air vehicle 2000. The unmanned aerial vehicle 2000 has a main body 2001, a rotary wing portion 2002, an image pickup device 500, and a motor 10. The motor 10 rotationally drives the rotary blade portion 2002. Since the unmanned aerial vehicle 2000 has a motor 10, it can fly with low vibration. The unmanned aerial vehicle 2000 is capable of high-precision imaging while flying with low vibration.

The motor 10 to which the present invention is applied is used, for example, in an electric assist device. FIG. 10 is a front view of the electrically power assisted bicycle 3000, which is an example of the electrically power assisted device. The electrically power assisted bicycle 3000 is a bicycle that assists a person by using a motor.

The electrically assisted bicycle 3000 includes a microprocessor 200 which is a signal processing device, the motor 10 described above, and a battery 40, in addition to the parts provided in a general bicycle. Examples of parts provided in a general bicycle are a handle 100, a frame 11, a front wheel 12, a rear wheel 13, a saddle 14, a chain 15, a pedal 16, and a crank 17. The rear wheel 13 is mechanically connected to the motor 30 via a chain 15. The rear wheel 13 is rotated by the human-powered torque applied by the pedal 16 and the motor torque applied by the motor 10. As a result, the electrically power assisted bicycle 1 is driven.

Since the electrically power assisted bicycle 3000 has the above-mentioned motor 10, it is driven with low vibration and the riding comfort is improved.

Although the preferred embodiments according to the present invention have been described above with reference to the accompanying drawings, it goes without saying that the present invention is not limited to the above examples. The various shapes and combinations of the constituent members shown in the above-mentioned examples are examples, and can be variously changed based on design requirements and the like without departing from the gist of the present invention.

1N, 1S ... shatterproof part, 2N, 2S ... notch, 10 ... spoke type motor (motor), 30 ... rotor, 31 ... shaft, 32 ... rotor core, 33A, 33B ... permanent magnet, 34, 34N, 34S ... core piece Department, 40 ... Stator, 2000 ... Unmanned flying object, 3000 ... Electric assisted bicycle (electrically assisted device), C ... Center line, J ... Central axis

Claims (10)

With the stator
A rotor that can rotate relative to the stator about a central axis extending in the vertical direction is provided.
The rotor includes a shaft arranged along the central axis, and a rotor core having a plurality of core piece portions arranged radially outward of the shaft so as to be separated from each other along the circumferential direction.
A plurality of permanent magnets arranged alternately with the core piece portion in the circumferential direction on the radial outer side of the shaft to excite the core piece portion, and
With
The core piece portion includes a shatterproof portion that covers a part of the radial outer side of the permanent magnet.
From a position where the distance in the circumferential direction from the circumferential center line of the permanent magnet covered by the shatterproof portion to the radial outside of the shatterproof portion is longer than the end portion of the shatterproof portion to the center line. With a notch placed facing,
Spoke type motor. Let Δθ be the angle between the center line of the permanent magnet and the far end of the notch in the circumferential direction, let P be the logarithm of the permanent magnet, and let N be the order of the electrical angle.
0.5 × (π / P) × (1 / N) ≦ Δθ ≦ 1.5 × (π / P) × (1 / N)
The spoke type motor according to claim 1, which satisfies the above relationship. The spoke-type motor according to claim 1 or 2, wherein the end of the notch on the side close to the center line in the circumferential direction is radially outside the permanent magnet and overlaps the permanent magnet in the radial direction. According to any one of claims 1 to 3, the end portion of the notch portion on the side far from the center line in the circumferential direction is radially outside the permanent magnet and overlaps the permanent magnet in the radial direction. The spoke type motor described. The spoke-type motor according to any one of claims 1 to 4, wherein the shatterproof portion is provided in the entire axial direction of the rotor core. The spoke-type motor according to any one of claims 1 to 4, wherein the shatterproof portion is provided in a part of the rotor core in the axial direction. The spoke-type motor according to any one of claims 1 to 6, further comprising a second shatterproof portion that covers a part of the radial outer side of the permanent magnet with a resin material. A vehicle motor comprising the spoke-type motor according to any one of claims 1 to 7, as a motor for driving the dual clutch transmission. An unmanned aerial vehicle comprising the spoke-type motor according to any one of claims 1 to 7. An electric assist device comprising the spoke type motor according to any one of claims 1 to 7.

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